According to Gingerich, the book published in 1609 was in essence the first ever to introduce physical principles into the study of astronomy.

FORBES: Kepler, Mars and the Turning Point in Astronomy

Mr. DREHER: Well, I'll tell you, the reason that we have Lent, such an austere Lent, is to remind us that, you know, we aren't slaves to our appetite, that we should subordinate our material needs and our physical appetites to higher spiritual principles.

NPR: For Spring, an Attempt to Forgo Meat

For Arsenal, this performance and result will have only made Wenger - who was given noisy vocal backing throughout the game - even more entrenched in his belief that he will not sacrifice his principles for a more physical style of play.

BBC: Arsenal 2-1 Man Utd

The conference aimed to translate into action the principles of the International Charter of Physical Education and Sport, the Olympic Charter and other international instruments.

UNESCO: Social and Human Sciences